As operators move from the realm of being video-only providers to serving up data and telephony, they should consider the option of DC powering for multiple services There was a time when cable was simple. Operators had virtual monopolies, so competition was not an issue. They delivered a single programming feed, leaving any sorting out to be done at the set-top. And powering headend or hub equipment was nearly as simple as plugging a toaster into an AC outlet. | white paper As operators move from the realm of being video-only providers to serving up data and telephony they should consider the option of DC powering for multiple services There was a time when cable was simple. Operators had virtual monopolies so competition was not an issue. They delivered a single programming feed leaving any sorting out to be done at the set-top. And powering headend or hub equipment was nearly as simple as plugging a toaster into an AC outlet. A Whole New World That was then. Today competition is intense and becoming ferocious. Cable companies are expected to deliver advanced video services voice and data just to stay competitive. And if subscribers aren t satisfied with what one provider offers they can turn to overbuilders satellite broadcasters or a phone company for what they want. Not surprisingly power requirements are changing along with everything else. Operators have some complex choices to make. But there s one area where there is no choice powering telephony equipment. Telephony has never used AC. It uses -48 VDC and chances are it always will. In other words operators planning to offer the telephony services that subscribers demand will have to power equipment with -48 VDC. Why Not the Works Most electronic equipment is already DC. Even if it plugs into an AC outlet it uses an internal power supply to convert AC to the DC it needs. The change taking place today is in where that conversion takes place. There are good reasons to convert headends and hubs to DC power and in spite of the conversion cost some savvy operators are doing just that. Although many operators continue to rely mostly on AC the future clearly favors DC power in headend and hub facilities. DC powering for nontelephony equipment only began appearing in the mid-1990s. It takes some getting used to but because it fits so well with the direction of today s markets operators should at least consider the DC power option. Power Equipment Primary Power Secondary .
